This research proposal is designed to elucidate the mechanisms involved in the pathogenesis of hypertensive vascular disease. Previous work from this laboratory has indicated that the differential response of the arterial vasculature to hypertension is related to arterial caliber, permeability pathways, mechanical effects of elevated pressure and the vasculotoxic (vasoconstrictor) action of angiotensin II. These studies will now be extended to explore in one and two kidney Goldblatt hypertension in the rat the following projects: (1) The reaction of the coronary circulation (epicardial arteries, intramyocardial arteries and arterioles, and capillaries) as well as myocardium will be explored by means of electron microscopy, probe molecules, radioautography and morphometry; (2) The origin and composition of glomerular and vascular hyalin at the cellular level will be examined by means of labeling studies, in vivo and in vitro radioautography and enzyme digestion; and (3) The identification of contractile and relaxing proteins within arterial endothelium in hypertension will be studied by means of immunohistology and immunocytology. BIBLIOGRAPHIC REFERENCES: Giacomelli, F., Anversa, P. and Wiener, J. Interendothelial gap size of subendocardial vs subepicardial capillaries. Microvascular Res. 10:38-42, 1975. Anversa, P., Giacomelli, F. and Wiener, J. Intercellular junctions of rat endocardium. Anat. Record 183:477-484, 1975.